1. Field of the Invention:
This invention relates to consumable hot tops as positioned in the upper ends of ingot molds for maintaining a pool of molten melt in desirable position in the cooling ingot.
2. Description of the Prior Art:
Prior art hot top constructions have comprised a variety of devices for the intended purpose. Several of these have used wedges to position the side board sections of the hot top in the ingot mold. See for example U.S. Pat. No. 3,797,801 in which a pair of corner post devices are used to cooperate with the foldable wall sections to produce a hot top enclosure.
In U.S. Pat. No. 4,121,805 a self adjusting consumable hot top includes shape adjusting sections and wedges for securing them in wedged position in an ingot mold.
Still other forms of hot tops may be seen in U.S. Pat. No. 3,478,999 wherein the corner portions of the hot top space the side board panels and U.S. Pat. No. 3,165,798 wherein the consumable hot top is formed of inter-engaging portions which are moved into desired relation by tapered wedges inserted at the corners.
In the present disclosure side board sections of a consumable hot top are formed with novel end configurations designed to receive and be wedged by novel corner pieces, both of which end sections of the side boards and the corner pieces can be formed with relatively simple dies.
In the prior art, in constructions generally used, the corner pieces or wedges, such as seen for example in U.S. Pat. No. 3,797,801, have their vertical sides or contact surfaces at an angle greater than 90.degree. to the inner surface thereof. Such corner pieces or wedges are difficult to form of consumable material because their shape prohibits their ready removal from a die cavity in which they are formed unless a multi-part die is used and operated to permit the formed product to be released. Of equal importance is the inherent problem in installing the heretofore conventional corner pieces or wedges between the side boards in positioning a consumable hot top in an ingot mold. The mold itself is tapered and often of irregular inner configuration. The corner pieces or wedges therefore loosely engage the edges of the ends of the side boards and are not easily retained in the desired position during the simultaneous positioning of the side boards and the corner pieces in the open upper end of the ingot mold. With the invention disclosed herein, the abutting ends of the side boards are formed with configurations which tend to confine or limit movement of the corner pieces or wedges and prevent their accidental dislocation from the desired areas during installation. The corner pieces or wedges as disclosed herein are formed with their longitudinal side edges at less than 90.degree. to their inner surfaces and are thereby self-retaining in the desired location. Additionally, yieldable metal holders, such as sections of wire, positioned transversely of the corner pieces, serve to increase the initial frictional engagement of the corner pieces or wedges against the vertical tapered edges of the side boards of the hot top.
None of these advantages are found in the prior art constructions.